a medical librarian's adventures in evidence-based living

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This is a crazy long post. Take my husband's advice & pour yourself a big cup of coffee before reading this one!

Here we go again, folks!

Once more it's time to reconsider the value of getting that annual mammogram.

I thought this was settled in 2009. Well, not really. We all balked at the new guidelines and stuck our heads in the sand.

So, once again Dr. H. Gilbert Welch, the Dartmouth risk communication "give 'em the facts" maven ran the numbers to show us in black & white how little benefit we actually get from screening mammograms.

But wait: Just so you know--Welch is NOT talking about diagnostic mammograms--that's what a women gets when she finds a lump, has a symptom, or her doctor thinks there's a good reason to have a mammogram. He's talking about screening mammograms--what healthy women start getting at age 40 or 50.

Should I or shouldn't I? Should I follow the new U.S. Preventive Task Force Guidelines and get screened less? More about that later in the post.

Thanks to Dr. H. Gilbert Welch's latest study in the Archives of Internal Medicine--and a host of breast cancer experts--it's now a little clearer to me why that annual screening mammogram is not the savior I once thought it was. Click here for the complete article.

And don't miss Tara Parker-Pope's latest article on screening mammography, "Mammogram's Role as Savior is Tested," New York Times, October 24, 2011. Click here for the complete article.

So who is Dr. H. Gilbert Welch, anyway? The Dartmouth University Institute of Health Policy & Clinical Practice professor is one of the leading authorities on health screening, risk communication, overdiagnosis, & health policy--and his latest article (sure to stir up controversy) was just published online Oct. 24, 2001 in the Archives of Internal Medicine. Click here for his bio.

Bottom Line:

In spite of all the testimonials from women who believe their lives have been saved by an annual mammogram--that's not the reality.

Sure, mammograms find cancerous cells, precancerous cells, and solid tumors--but, according to many experts, much of what's found isn't life-threatening--and the rest of what's found would likely be found & treated without a screening mammogram. And, unfortunately, many of the fast-growing aggressive cancers are not picked up on screening mammograms.

[Although] "some women are helped by mammography screening--those numbers are lower than most people think."

"Most women with screen-detected breast cancer have not had their life saved by screening. They are instead either diagnosed early (with no effect on their mortality) or overdiagnosed."

Using National Cancer Institute (NCI) software & cancer incidence & mortality data from the SEER National Cancer Registry, Welch estimated a woman’s 10-year risk of developing breast cancer and her 20-year risk of death, factoring in the added value of early detection based on data from various mammography screening trials as well as the benefits of improvements in treatment.

Here's what he found:

"Among the 60 percent of women with breast cancer who detected the disease by screening, only about 3 percent to 13 percent of them were actually helped by the test." (Oct. 24, 2011 NYT)

But Welch clarifies this in his article, saying, [B]ased on "recent European data, the probability that a woman with "screen-detected" breast cancer has, in fact, avoided a breast cancer death is more likely well below 10%." For the European studies, click here and here.

Although those numbers are not inconsequential, they represent just a small portion of the 230,000 women given a breast cancer diagnosis each year, and a fraction of the 39 million women who undergo mammograms each year in the United States.

Dr. Welch says it’s important to remember that of the 138,000 women found to have breast cancer each year as a result of mammography screening, 120,000 to 134,000 are not helped by the test." (Oct. 24, 2011 NYT)

Here's the conclusion of a very recent European study on screening mammography:

"The contrast between the time differences in implementation of mammography screening and the similarity in reductions in mortality between the country pairs suggest that screening did not play a direct part in the reductions in breast cancer mortality." BMJ 2011 Jul 28;343:d4411. doi: 10.1136/bmj.d4411

Making It Personal

My annual mammogram is scheduled for March 2012. Since age 50 I've never skipped a year.

But, after spending a couple of hours reading what breast cancer and medical screening experts have to say about the real value of the annual mammogram--I think I finally "get" why it's OK to limit my screening to every other year.

Over-diagnosis of innocuous cancers isn't without risks. I don't want to push the envelope any more than is necessary.

You know what I mean. The repeat mammograms, ultrasounds, biopsies, anxieties, lumpectomies, tamoxifen, Arimidex, radiation, chemo. I'm glad to now have the real facts--and to know what screening mammograms are good at, what they miss--and what findings to question.

But, on the other hand...I'm in the 60-69 age group--that's the group that sees the greatest benefits in mammography. So, I'll have to let you know what I decide to do in March. I'm guessing I'll have the mammogram--but at least I'll have the facts.

Why So Little Information on Prevention? Get That Mammogram is Mostly What We Hear!

It looks like we've been oversold on the value of the annual screening mammogram. And certainly no one but Dr. Welch tells us about the risks.

It does a great job of finding microscopic precancerous lesions like Ductal Carcinoma In Situ (DCIS) that often don't progress to invasive cancer--but once they're found on a mammogram they're treated. Read more about DCIS here.

The really fast-growing aggressive cancers are often missed because they aren't visible at the time of an annual mammogram--so screening is often of no help for these "bad cancers." "Roughly 15-20% of breast cancers are deadly," according to Dr. Susan Love in the Oct. 24, 2011 NYT.

Many cancers are slow-growing and can be found and successfully treated when they're discovered either in that every-other-year mammogram or with a breast exam.

And here's the kicker! Mammograms are diagnostic tools--they don't do a single thing to help women prevent cancer. There is plenty of research pointing to real strategies that can help us prevent breast cancer--yet, how often do we hear about them?

Dr. Susan Love, the prominent breast cancer surgeon & women's advocate who is a Clinical Professor of Surgery at UCLA, "says the scientific understanding of cancer has changed in the years since mammography screening was adopted."

As a result Love would like to see less emphasis on screening and more focus on cancer prevention and treatment for the most aggressive cancers, particularly those that affect younger women. Roughly 15 to 20% of breast cancers are deadly. (Oct. 24 NYT)

Here are just a few of the prevention strategies that research has shown to reduce the risk of breast cancer.

3. Limiting alcohol consumption. From the Nurses’ Health Study: alcohol converts androgens to estrogens; 1 to 1.5 drinks per day is associated with a 19% nonsig­nificant increase in risk for breast cancer; 2.5 to 4 drinks per day is associated with a 41% increase in risk for breast cancer; and some studies show synergistic effect with hormone therapy. Update 11/01/11: A new study published in JAMA shows that women who routinely have even small amounts of alcohol, as few as three drinks a week, have an elevated risk of breast cancer. Click here to read more.

6. Eating a diet high in fruits, vegetables, & vegetable proteins makes a difference. A hot-off-the-press article in the American Journal of Epidemiology looked at the incidence of breast cancer in the long-running Nurses' Health Study & found the risk of developing the "harder to treat" estrogen-negative breast cancer was reduced by 20% in woman who ate the highest amounts of vegetable protein, like beans, soy, & nuts--and the highest numer of fruits & vegetables.

Two years ago an expert panel of physicians advised the U.S. Preventive Services Task Force that women should be screened for breast cancer starting at age 50, instead of at age 40. They nixed the once-a-year mammogram, in favor of every other year. After age 74--its value was questionable.

Instead of having 35 mammograms over a lifetime--the new guidelines meant women would have only 13 mammograms over a lifetime.

Click herefor the recommendations, which were based on scientific research--not financial savings.

The U.S. Preventive Task Force Recommends We Change the Game Plan

"There is convincing evidence that screening with film mammography reduces breast cancer mortality, with a greater absolute reduction for women aged 50 to 74 years than for women aged 40 to 49 years.

The strongest evidence for the greatest benefit is among women aged 60 to 69 years.

Among women 75 years or older, evidence of benefits of mammography is lacking."

When these guidelines came out women everywhere went ballistic! Look, we all know someone whose life was saved by a mammogram.

Why would anyone want to miss a single "mammographic" opportunity? What possible harm could there be in getting screened every year? I'll leave that one to Dr. H. Gilbert Welch and the breast cancer experts to further explain.

As it turned out, the USPTF recommendations quickly withered on the vine--blasted by the Susan Komen Foundation, and women everywhere. We all wanted our annual reassurance that we had dodged the breast cancer bullet!

And we wanted our lives saved by early detection, if it turned out we had breast cancer! Is a once-a-year screening too much to ask for? Start the mammograms at age 40--not 50--we demanded. Physicians & the USPTF backed down.

Which is exactly why Dr. H. Gilbert Welch wasn't backing down. He ran the numbers again--and this time with fancy National Cancer Institute software, so we could have the real story about the value of screening mammograms. But, who knows if anyone will listen.

The Down-Side of Over-Screening

As it turns out--screening for breast cancer is more complicated than any of us realized when we flipped out over the USPTF guidelines back in 2009.

It's not infallible--and there's a real risk of overdiagnosis. If we limited screening to the women most at risk--the 50-74 year olds--and we cut it down to every-other-year, lives would still be saved, and we might cut down on some of the risks of overdiagnosis.

OK--I know I'm repeating myself! I want to drill this into my own brain. Not all the breast cancers found are going to cause us harm! And mammograms do a fantastic job of finding innocuous breast cancers. Yes, it's true, not all breast cancers are deadly. But treating innocuous precancerous cells may cause harm. I think that's the hardest part to understand.

"The evidence review suggests that for every 2000 women invited to screening for 10 years, one death from breast cancer will be avoided, but that 10 healthy women will be overdiagnosed with cancer. This overdiagnosis is estimated to result in six extra tumorectormies and four extra mastectomies and in 200 women risking significant psychological harm relating to the anxiety triggered by the further investigation of mammographic abnormalities." (Welch. Over-Diagnosed, pg. 88)

Knowing what she knows, Dr. Heath has "turned down her invitations" to have a mammogram, but she worries that she made the decision to skip the mammogram based on information that her patients don't have.

There's no doubt that mammograms save lives--just not the number we think they do. And truth be told--improved breast cancer treatments are what's really saving lives--not the annual screenings.

"One of the reasons screening doesn't make much difference is that advances in breast cancer treatment make it possible to save even many women with more advanced cancers.

According to Dr. Laura Esserman, "Screening is but one of the tools that we have to reduce the chance of dying of breast cancer. The treatments that we have actually make up for a good deal of the benefits of screening."NYT, Oct. 24, 2011

How Is It Possible That Finding Cancer Earlier Isn't Better?

Here's what finally made sense to me--and why my "eyes are now wide-open" when it comes to my annual mammogram.

"Screening mammograms preferentially find cancer that are slowly growing, and those are the ones that are seldom deadly. Getting something noxious out of the body as soon as possible leads women to think screening saved their lives. That is most unlikely."

Not helped by screening mammograms: the slow-growing cancers that would be found & successfully treated with or without screening.

Not helped by screening mammograms: the aggressive deadly cancers--it doesn't matter if they are found early by screening--or later, from a lump or other symptoms. (Roughly 15-20% of breast cancers are deadly.)

Overdiagnosed by screening mammograms--and possibly causing harm: the innocuous cancers that won't cause harm--they won't grow or spread--and some disappear on their own. These are the ones that show up as tiny dots on a mammogram--and once discovered--they're almost always treated. A far as I know, there's no watch & wait policy with breast cancer, as there is with prostate cancer. These microscopic dots are often Ductal Carcinoma In Situ (DCIS)--the microscopic breast cancer that hasn't moved out of the ducts of the mammary gland. Some doctors think DCIS can become invasive--but others believe it only does so infrequently. The data suggests 1/3 becomes invasive--but all DCIS is treated almost as aggressively as invasive cancer, according to Welch. (Welch, Over-Diagnosed, pg. 86) See also the Norwegian mammography study that showed 20% of breast cancers naturally disappear without treatment, owing to the bodies own defenses. As the resolution of mammography gets better--overdiagnosis increases.

The cancers helped by mammography: the small fraction of aggressive fast-growing deadly cancers that will only be helped when "by chance & perfect timing" they are discovered at exactly the time one's mammogram is scheduled. We all know women who discover a lump or a symptom in between mammograms--and they wonder how the mammogram missed their cancer. It's often the fast-growing aggressive kind.

Here's the final point Welch wants us to understand: It's easy to be fooled into thinking that screening mammograms are saving lives. Mammograms found breast cancer in my friend, neighbor, co-worker, sister, and celebrities everywhere.

"Today more people are likely to know a cancer survivor than ever before.

Breast cancer survivors are particularly common: they now represent approximately 2.5 million, or one-fifth of the current survivor population.

Earlier diagnosis (either via enhanced awareness or screening) and better treatment are clearly part of the explanation for this large survivor population.

But, so too is the enthusiam for screening--and the resulting overdiagnosis. And, ironically, this enthusiasm may, in turn, be the product of a large number of survivors.

This self-reinforcing cycle (the more detection, the more enthusiam--the so-called popularity paradox of screening) is driven, in part, by the presumption that every screen-detected breast cancer survivor has had her "life-saved" because of screening.

Our analyses suggest this is an exaggeration.

In fact, a woman with screen-detected cancer is considerably more likely not to have benefited from screening.

We believe that this information is important to put cancer survivor stories in their proper context."

Comments

The mammogram-breast cancer information trends pretty well with the PSA-prostate cancer information- a few are saved, a large number over-treated, and most who are screened and/or treated do not in fact benefit. I have worked with cultured cancer cells and can tell you that if they are aggressive, they do not wait to spread until the tumor can be felt. As soon as a few cells can break off into the bloodstream and go elsewhere, if they have the right mutations, they will. Slow-growing lumps that will not go anywhere are easy to find and treat. Tiny clumps of cells that grow and spread fast ... almost impossible to find in time.
I'll probably have one mammogram (if they can't find a better screening test by then) between ages 55 and 60, unless I find a symptom beforehand. My mom had a very painful mammogram at 55, and picked up a nasty skin infection from the machine. She says she'll never have another, and she'll probably be fine. Being familiar with your own body, and treating it properly with rest, exercise and food, are the best possible preventions.

I personally know family members whose aggressive breast cancer was only detected via mammogram. Had they not had the mammogram, they would not be alive today. The overall statistics really don't matter when you or a loved one are in fact one of the ones saved. That said, I'd love to NOT have mammograms. Now (at age 55) I alternate mammography with thermography and my gynecologist is okay with that approach. My mom is in remission from breast cancer so I don't feel I can stick my head in the sand and go by statistics. Finally, I agree that little is done in they way of education/promotion prevention of breast cancer or ANY cancer. The focus is on "the cure," when in reality prevention is the biggest part of the solution.

I don't know whether screening mammography saved my life or not, but it did spare me the need for chemotherapy. I regard this as a huge advantage, but I never see this, or the possibility of avoiding radiation treatment, mentioned as possible benefits of early diagnosis. My breast cancer was an invasive lobular (not ductal) cancer, 1.8 cm when found, not palpable. It did not appear on the mammogram for the previous year. Sooner or later it would have grown large enough to be palpable, or it would have been picked up an a later mammogram had I skipped the mammogram that year. Maybe (probably?) it could have been treated successfully at that point -- but that treatment would have included chemotherapy. And it might have included radiation if I'd had positive lymph nodes by then. As it was, I had a mastectomy (hence no need for breast radiation) and sentinal lymph node biopsy, followed by two years of tamoxifen and 3 years of arimidex. I consider myself extremely lucky. It's been almost 7 years since diagnosis and so far there is no evidence of recurrence.

"And the answer is a resounding yes. To get you the best possible information, I turned to registered dietitians Sally Scroggs, MS,RD,LD, and Clare McKinley, RD,LD, at the University of Texas M.D. Anderson Cancer Center, one of the leading cancer hospitals in the world. They explained that breast cancer risk could be decreased by up to 38% through lifestyle factors including maintaining a healthy weight, exercising regularly, and eating a healthy diet. In fact, less than 10% of breast cancer appears to have a genetic basis."

Excellent compilation of this material! Dr. H. Gilbert Welch's wife is a breast cancer survivor which makes his recommendations against screening mammograms all the more compelling. I highly recommend his book "Overdiagnosed" which has some eye opening information about all of the screening tests.

My experience (I live in Germany):
I had an aggressive form of breastcancer at age 34 (invasive ductal, G3, Ki67 70%: really aggressive).
It was a lump of 3cm and I found it myself (I was too young for screening anyway).
To the astonishment of all and despite enlarged lymphnodes, the lymphnodes where free. (At that time an extensive lymphadenektomy was standard and I suffer still from this procedure: oedema and problems with pain and lack of strength).
I had a mastektomie and three months of chemotherapy (because of the aggressiveness).
That was 17 years ago and I decided against mammograms (I had about 2 or 3 in all these years, when I was forced to submit for reasons of medical insurance in connection with certain procedures). In the first years after diagnosis I opted for sonogramms which makes sense in my case as I have very small breasts.
Except in very rare instances I don't believe screening makes a difference.
But as one can read in the comments here, the decisions seem to be very personal.

Thank you for your posts! I am always happy to find something new to read in your blog.
Can't wait for the Esselstyn oil free update (broad hint).

I can't thank you all enough for all of your thoughtful comments to this post--the ones sent directly to me--and those that you generously shared on the blog.

I'm away from home all day today--with no time to write, but I want to make sure those who read comments absolutely follow Doug's link to the CNN article written by an MD Anderson physician--with the help of 2 MD Anderson dietitian's.

MD Anderson is the #1 cancer hospital in the U.S.

I'll post the full article tonight or tomorrow since many don't read comments.

What he said made perfect sense to me both regarding mammograms and prostate screenings.

He spoke about how the medical technology industry has revved up for these screenings and will probably not back down. Big pharma joined the club and together, they are a force not to be tampered with. There is too much money and too much business to be had, but thank goodness, we have some truthful voices out there that help us make our decisions.

Personally, I have walked through the fire of a mis-diagnosis, a biopsy that found nothing, and all the anxiety that went along with all those weeks of torturous stress.

I still have mammograms, but only every other year. My doc is very careful and thorough with my breast exams as am I.

My plant-strong diet and my exercise routines have given me added confidence but no one is bullet-proof. It's a slippery slope out there but ultimately we have to make our own decisions...we are responsible.

With excellent, current information presented here on your site along with truth-seekers like Dr. Welch, the medical field is not so mysterious anymore. Thank you once again, Deb.

Nurse thank you for your blog. I am always affected by what you share. A few years ago at age 40 my first mammo detected the lump I'd felt 10 years prior (I had no health insurance at that time so my relationship to my body through touch was all I had). That first mammo resulted in being "diagnosed" with possible phyllodes tumor or fibro-adenoma (normal breast density as it was explained to me). It was also "explained" by the most de-humanized robot surgeon that it might never be determined, even under microscope post-op, what the "lump" might be. Due to this vague maybe diagnosis, I resisted lumpectomy and a few years later wonder if I am the "over-diagnosed." I have my yearly mammo and sonogram, and regularly touch my lump that I first felt over 15 years ago. I don't have doctor-worship that would have me get the lumpectomy. It made me think they wanted to just be safe and not get sued for malpractice, it all felt so vague and unclear. The research you share at least makes me feel like I'm not crazy! Thank you for the constant reminder to eat well and plant-based and to exercise VIGOROUSLY. It is what makes us alive.

My sister in law had a clean mammogram in June of 2004; in September of that year she was diagnosed with an aggressive breast cancer, and she died in March of 2005. The mammogram did not find her cancer.

I'm so sorry to hear about your sister-in-law. That's what the breast cancer researchers tell us--often mammograms are no defense against the most aggressive breast cancers. The best we can do is just make effort to follow the few preventive lifestyle guidelines out there.